BEGIN:VCALENDAR VERSION:2.0 PRODID:-//TYPO3/NONSGML Calendarize//EN BEGIN:VEVENT UID:calendarize-hodge-riemann-relations-for-convex-valuations DTSTAMP:20240604T141101Z DTSTART:20240703T171500Z SUMMARY:Hodge-Riemann relations for convex valuations DESCRIPTION:Vortragsankündigung\n \nIm Rahmen des Kolloquiums spricht\n \nHerr Prof. Dr. Andreas Bernig (Uni Frankfurt)\nüber\n \nHodge-Riemann relations for convex valuations\n \nThe so-called Kähler package consist s of a Poincaré duality\, a hard Lefschetz theorem and the HodgeRiemann r elations. The origin goes back to the cohomology theory of compact Kähler manifolds\, but similar structures appeared in the last few years in many different areas in mathematics such as algebraic geometry\, combinatorics and polytope theory and have far reaching consequences.\n \nAfter explai ning some of these structures\, I will report on a recent project with Jan Kotrbatý (Charles University Prague) and Thomas Wannerer (Friedrich-Schi ller University Jena) where we introduce a Kähler package for convex valu ations. As a consequence\, we find quadratic inequalities for mixed volume s that generalize the fundamental Alexandrov-Fenchel inequality.\n \nDer Vortrag findet statt am\nMittwoch\, 03.07.2024 um 17.15 Uhr im Raum W01 0- 006\nKaffee/Tee um 16.45 Uhr im Raum W1 2-213\n \nInteressierte sind herz lich eingeladen.\n X-ALT-DESC;FMTTYPE=text/html:

Vortragsankündigung

Im Rahmen des Kolloquiums spricht

\n< h3 class="text-center">Herr Prof. Dr. And reas Bernig (Uni Frankfurt)\n

< span class="fontstyle1">über

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Hodge-Riemann relations for convex valuations

The so-ca lled Kähler package consists of a Poincaré duality\, a hard Lefschetz th eorem and the HodgeRiemann relations. The origin goes back to the cohomolo gy theory of compact Kähler manifolds\, but similar structures appeared i n the last few years in many different areas in mathematics such as algebr aic geometry\, combinatorics and polytope theory and have far reaching con sequences.

After explaining some of these structures \, I will report on a recent project with Jan Kotrbatý (Charles Universit y Prague) and Thomas Wannerer (Friedrich-Schiller University Jena) where w e introduce a Kähler package for convex valuations. As a consequence\, we find quadratic inequalities for mixed volumes that generalize the fundame ntal Alexandrov-Fenchel inequality.

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Der Vortrag find et statt am

Mittwoch\, 03.07.2024 um 17.15 Uhr im Raum W01 0-006

Kaffee/Tee um 16.4 5 Uhr im Raum W1 2-213

Interessierte sind h erzlich eingeladen.

\; LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-norddeutsches-kolloquium-2024 DTSTAMP:20240513T130404Z DTSTART;VALUE=DATE:20240628 DTEND;VALUE=DATE:20240630 SUMMARY:Norddeutsches Kolloquium 2024 DESCRIPTION:In 2024\, this colloquium will be held in Oldenburg\, from Jun e 28 to 29 on the Wechloy campus of the CvO University. The program includ es a variety of presentations on different topics that reflect the diversi ty and breadth of research in this field. From basic concepts to advanced applications\, the talks and posters offer insights into various aspects o f applied mathematics and numerics.\nLocal organizers:\nProf. Dr. Alexey C hernov\, Prof. Dr. Hannes Uecker\, Dr. Frank Schöpfer\, Alexander Meiners \, Tùng Lê.\nThe program begins on Friday\, June 28\, at approximately 1 pm.\nIn addition to the lectures\, a poster session is also planned.\nAft er the lectures there will be a joint dinner on Friday.\nOn Saturday\, Jun e 29\, the program will continue until approx. 12 noon.\nVenue: Institute of Mathematics\, Campus Wechloy\nEvent Link: NoKo 2024 in Oldenburg\n\n X-ALT-DESC;FMTTYPE=text/html:

In 2024\, this colloquium will be held in Oldenburg\, from June 28 to 29 on the Wechloy campus of the CvO University . The program includes a variety of presentations on different topics that reflect the diversity and breadth of research in this field. From basic c oncepts to advanced applications\, the talks and posters offer insights in to various aspects of applied mathematics and numerics.

Local orga nizers:

Prof. Dr. Alexey Chernov\, Prof. Dr. Hannes Uecker\, Dr. F rank Schöpfer\, Alexander Meiners\, Tùng Lê.

The program begins on Friday\, June 28\, at approximately 1 pm.

In addition to the l ectures\, a poster session is also planned.

After the lectures the re will be a joint dinner on Friday.

On Saturday\, June 29\, the p rogram will continue until approx. 12 noon.

Venue: Institute of Ma thematics\, Campus Wechloy

Event Link: NoKo 2024 in Oldenburg

\n\n LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-patterns-interfaces-and-dynamics DTSTAMP:20240521T095551Z DTSTART:20240522T171500Z SUMMARY:Patterns\, interfaces and dynamics DESCRIPTION:Vortragsankündigung\n \nIm Rahmen des Kolloquiums spricht\n \nHerr Jens Rademacher (Universität Hamburg)\n \nüber\n \nPatterns\, i nterfaces and dynamics\n \nPatterns\, as coherent structures in space and time\, permeate our perception and the physical world. We sense sound and vibration waves\, and we organise observations in patterns and symmetries . Nonlinear effects enter when these are “far" from equilibrium\, leadin g to self-organized emergent phenomena as in water waves\, vegetation patt erns\, and action potentials. Paradigmatic nonlinear structures are interf aces that separate regions of different patterns\, such as material phase boundaries or magnetic domain walls. In this talk I take a mathematical pe rspective and introduce some concepts\, approaches\, and results from this fascinating field.\n \nDer Vortrag findet statt am\n \nMittwoch\, den 2 2.05.2024 um 17.15 Uhr im Raum W01 0-006\n \nKaffee/Tee um 16.45 Uhr im R aum W01 2-213\n \nInteressierte sind herzlich eingeladen X-ALT-DESC;FMTTYPE=text/html:
Vortragsankündigung
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Im Rahmen des Kolloquiums spricht
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\n< h4 class="text-center">Herr Jens Rademach er (Universität Hamburg)\n
&nb sp\;
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über
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Patterns\, interfaces and dynamics\n
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Patterns\, as coherent structures in space and time\, permea te our perception and the physical world. We sense sound and vibration wav es\, and we organise observations in patterns and symmetries. Nonlinear ef fects enter when these are “far" from equilibrium\, leading to self-orga nized emergent phenomena as in water waves\, vegetation patterns\, and act ion potentials. Paradigmatic nonlinear structures are interfaces that sepa rate regions of different patterns\, such as material phase boundaries or magnetic domain walls. In this talk I take a mathematical perspective and introduce some concepts\, approaches\, and results from this fascinating f ield.
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Der Vortrag findet statt am
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Mittwoch\, den 22.05.2024 um 17.15 Uhr im Raum W01 0-006
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Kaffee/Tee um 16.45 Uhr im Raum W01 2-213
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Interessierte sind herzlich eingeladen

LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-insuring-model-uncertainty DTSTAMP:20240513T130313Z DTSTART:20240515T171500Z SUMMARY:Insuring Model Uncertainty DESCRIPTION:Model uncertainty\, also known as Knightian uncertainty\, has become a major research topic in recent years. On the decision-theoretic s ide\, various approaches show how one can successfully capture model uncer tainty with the help of mathematical models. The lecture reviews recent mo del of preferences under Knightian uncertainty. These approaches are close ly related to attempts to quantify risk in finance.\nA particular focus wi ll be on the so-called smooth model\, an ambiguity-averse version of a sec ondorder Bayesian Ansatz\, that goes back to Klibanoff\, Marinacci\, and M ukerji (Econometrica 2005). We will study its axiomatic foundations and di scuss the relationship of this approach with statistics\, in particular th e issue of identification of models (Denti\, Pomatto\, Econometrica 2022). Moreover\, we show how the smooth model is related to variational and coh erent risk measures.\nWe then investigate consequences of model uncertaint y for the insurance market. We study the case where the typical consumer i n the economy is ambiguity-averse with smooth ambiguity preferences and th e set of priors is point identified\, i.e.\, the true law can be recovered ex post empirically from observed events. The identifiability of models a llows to write insurance contracts on models\, with important economic con sequences. We are able to construct a representative agent who\, in genera l\, has also smooth ambiguity preferences\, yet with a model-dependent amb iguity attitude. We illustrate our results in the classic Wilson framework of risk sharing where the representative agent has modelindependent ambig uity attitude and insurance against ambiguity can be explicitly computed.\ n\nDer Vortrag findet statt am Mittwoch\, den 15.05.2024 um 17.15 Uhr im R aum W01 0-006\nKaffee/Tee um 16.45 Uhr im Raum W1 2-213\nInteressierte sin d herzlich eingeladen. X-ALT-DESC;FMTTYPE=text/html:

Model uncertainty \, also known as Knightian uncertainty\, has become a major research topic in recent years. On the decision-theoretic side\, various approaches show how one can successfully capture model uncertainty with the help of mathe matical models. The lecture reviews recent model of preferences under Knig htian uncertainty. These approaches are closely related to attempts to qua ntify risk in finance.

A particula r focus will be on the so-called smooth model\, an ambiguity-averse versio n of a secondorder Bayesian Ansatz\, that goes back to Klibanoff\, Marinac ci\, and Mukerji (Econometrica 2005). We will study its axiomatic foundati ons and discuss the relationship of this approach with statistics\, in par ticular the issue of identification of models (Denti\, Pomatto\, Econometr ica 2022). Moreover\, we show how the smooth model is related to variation al and coherent risk measures.

We then investigate consequences of model uncertainty for the insurance marke t. We study the case where the typical consumer in the economy is ambiguit y-averse with smooth ambiguity preferences and the set of priors is point identified\, i.e.\, the true law can be recovered ex post empirically from observed events. The identifiability of models allows to write insurance contracts on models\, with important economic consequences. We are able to construct a representative agent who\, in general\, has also smooth ambig uity preferences\, yet with a model-dependent ambiguity attitude. We illus trate our results in the classic Wilson framework of risk sharing where th e representative agent has modelindependent ambiguity attitude and insuran ce against ambiguity can be explicitly computed.

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Der Vortrag findet statt am Mittwoch\, den 15.05.2024 um 17.15 Uhr im Raum W01 0-006

Kaffee/Tee um 16.45 Uhr im Raum W1 2-213

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Interessiert e sind herzlich eingeladen.
LOCATION: Raum W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-high-dimensional-approximation-making-life-easy-with-kerne ls DTSTAMP:20240219T133208Z DTSTART:20240320T170000Z SUMMARY:High dimensional approximation – making life easy with kernels DESCRIPTION:Im Rahmen des Kolloquiums spricht\nHerr Prof. Dr. Ian H. Sloan \, University of New South Wales (Sydney)\nüber\nHigh dimensional approxi mation – making life easy with kernels\n \nHigh dimensional approximati on problems commonly arise from parametric PDE problems in which the param etric input depends on very many independent univariate random variables. Often (as in the method of “generalized polynomial chaos”\, or GPC) th e dependence on the parametric variables is approximated by multivariate p olynomials\, leading to exponentially increasing difficulty and cost (expr essed as the “curse of dimensionality”) as the dimension increases. Fo r this reason sparsity of coefficients is a major focus in all implementat ions of GPC.\n \nIn this lecture we develop a different approach\, one in which there is no need for sparsification\, and no curse of dimensionalit y. The method\, proposed in a 2022 paper with Frances Kuo\, Vesa Kaarnioja \, Yoshihito Kazashi and Fabio Nobile\, uses kernel interpolation with per iodic kernels\, with the kernels located at lattice points\, as advocated long ago by Hickernell and colleagues.\n \nThe lattice points and the ker nels depend on parameters called “weights”. In the 2022 paper the reco mmended weights were “SPOD” weights\, leading to an L2 error independe nt of dimension but with a cost growing as the square of the number of lat tice points. A newer 2023 paper with Kuo and Kaarnioja introduced “seren dipitous” weights\, for which the cost grows only linearly with both dim ension and number of lattice points\, allowing practical computations in a s many as 1\,000 dimensions. The rate of convergence proved in the above p apers was of the order n-α/2\, for interpolation using the reproducing ke rnel of a space with mixed smoothness of order α. However\,a new result w ith Vesa Kaarnioja doubles the proven convergence rate to n-α.\n \nDer V ortrag findet statt am Mittwoch\, den 20.03.2024 \num 17.15 Uhr im Raum W0 1 0-006\n \nKaffee/Tee um 16.45 Uhr im Raum W1 2-213\n \nInteressierte s ind herzlich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Im Rahmen des Kolloquiums spricht
\n
He rr Prof. Dr. Ian H. Sloan\, University of New South Wales (Sydney)< /strong>
\n
über\n
High dimensional approximation – making life ea sy with kernels
\n
\ ;
\n
High dimensional ap proximation problems commonly arise from parametric PDE problems in which the parametric input depends on very many independent univariate random va riables. Often (as in the method of “generalized polynomial chaos”\, o r GPC) the dependence on the parametric variables is approximated by multi variate polynomials\, leading to exponentially increasing difficulty and c ost (expressed as the “curse of dimensionality”) as the dimension incr eases. For this reason sparsity of coefficients is a major focus in all im plementations of GPC.
\n
\;
\n
In this lecture we develop a d ifferent approach\, one in which there is no need for sparsification\, and no curse of dimensionality. The method\, proposed in a 2022 paper with Fr ances Kuo\, Vesa Kaarnioja\, Yoshihito Kazashi and Fabio Nobile\, uses ker nel interpolation with periodic kernels\, with the kernels located at latt ice points\, as advocated long ago by Hickernell and colleagues.
\n
\;
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The lattice points and the kernels depend on parameters calle d “weights”. In the 2022 paper the recommended weights were “SPOD” weights\, leading to an L2 error independent of dimension but with a cost growing a s the square of the number of lattice points. A newer 2023 paper with Kuo and Kaarnioja introduced “serendipitous” weights\, for which the cost grows only linearly with both dimension and number of lattice points\, all owing practical computations in as many as 1\,000 dimensions. The rate of convergence proved in the above papers was of the order n-α/2\, for interpolation u sing the reproducing kernel of a space with mixed smoothness of order α. However\,a new result with Vesa Kaarnioja doubles the proven convergence r ate to n-α.
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Der Vortrag findet statt am Mittwoch\, den 20.03.2024
\n
um 17.15 Uhr im Raum W01 0-006
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\;
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Kaffee/Tee um 16.45 Uhr im Ra um W1 2-213
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\;
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Interessierte sind herzlich eingeladen.
LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-dirk-langemann-1 DTSTAMP:20240219T133300Z DTSTART:20240131T171500Z SUMMARY:Vortrag: Dirk Langemann DESCRIPTION:Thema: "Mathematische Modellierung der Entwicklung metabolisch er Resistenzen" \nAbstract:\nDie Entwicklung von Resistenzen von beispiels weise Unkräutern und Bakterien wird als Anpassungsprozess an veränderte Umweltbedingungen modelliert. Die Kopplung von Wachstum und Vererbung für Genotypen\, die sich in mehreren Gen-Orten unterscheiden\, erlaubt die Er klärung beobachtbarer Szenarien. Das verwendetet System gewöhnlicher Dif ferentialgleichungen enthält zudem im Vererbungsmechanismus eine Tensorpr odukt-Struktur\, die zur Diskussion allgemeinerer Fragen der Modellierung einlädt.\nVortragender: Dirk Langemann\, TU Braunschweig\, Institut für Partielle Differentialgleichungen\nDer Vortrag findet statt am\nMittwoch\, den 31.01.2024 um 17.15 Uhr im Raum W01 0-006\nInteressierte sind herzl ich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Thema: "Mathematische Modellierung der Entwicklung metabolischer Resistenzen"
\n
Abstract:
\n
Die Entwi cklung von Resistenzen von beispielsweise Unkräutern und Bakterien wird a ls Anpassungsprozess an veränderte Umweltbedingungen modelliert. Die Kopp lung von Wachstum und Vererbung für Genotypen\, die sich in mehreren Gen- Orten unterscheiden\, erlaubt die Erklärung beobachtbarer Szenarien. Das verwendetet System gewöhnlicher Differentialgleichungen enthält zudem im Vererbungsmechanismus eine Tensorprodukt-Struktur\, die zur Diskussion al lgemeinerer Fragen der Modellierung einlädt.
\n
Vortragender: Dirk Langemann\, TU Braunschweig\, Institu t für Partielle Differentialgleichungen
\n
Der Vortrag findet statt am
\n
Mittwoch\, den 31.01.2024 \; um 17.15 Uhr im Raum W01 0-006
\n
Interessierte sind herzlich e ingeladen.
LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-prof-dr-dietmar-pfeifer-1 DTSTAMP:20240219T135230Z DTSTART:20240117T171500Z SUMMARY:Lecture: Prof Dr Dietmar Pfeifer DESCRIPTION:Title: "Generating unfavourable VaR scenarios under Solvency I I with patchwork copulas"\nAs the central idea of the presentation\, we pr esent a general\, simple patchwork construction principle for multivariate copulas\, with which unfavourable VaR (i.e. Value at Risk) scenarios are possible while maintaining the given risk-rank distributions. This is part icularly important for the so-called internal models or Pillar II (ORSA) u nder Solvency II. Since it seems unrealistic that the potentially absolute worst-case scenario will materialise in reality\, "almost worst-case" sce narios as addressed in this presentation are good modelling alternatives\, especially in higher dimensions. Our approach can be seen as a special ca se of the so-called ordinal sums\, which even represent the absolute worst VaR scenario in two dimensions. The lecture will be held in German.\nThe lecture will take place on\nWednesday\, 17 January 2024 at 5.15 pm in room W01 0-006\nCoffee/tea 16.45 in room W1 2-213\n \nInterested parties are cordially invited.\n X-ALT-DESC;FMTTYPE=text/html:
Title : "Generating unfavourable VaR scenarios under Solvency II with pat chwork copulas"
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As the cent ral idea of the presentation\, we present a general\, simple patchwork con struction principle for multivariate copulas\, with which unfavourable VaR (i.e. Value at Risk) scenarios are possible while maintaining the given r isk-rank distributions. This is particularly important for the so-called i nternal models or Pillar II (ORSA) under Solvency II. Since it seems unrea listic that the potentially absolute worst-case scenario will materialise in reality\, "almost worst-case" scenarios as addressed in this presentati on are good modelling alternatives\, especially in higher dimensions. Our approach can be seen as a special case of the so-called ordinal sums\, whi ch even represent the absolute worst VaR scenario in two dimensions. The l ecture will be held in German.
\n
The lecture will take place on
\n
Wednesday\, 17 January 2024 at 5 .15 pm in room W01 0-006
\n
Coffee/tea 16.45 in room W1 2-213
\n
\;
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~~Interested parties are cordially invited.~~
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LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-pd-dr-habil-joachim-kerner-1 DTSTAMP:20240219T135142Z DTSTART:20230712T171500Z SUMMARY:Lecture: PD Dr habil. Joachim Kerner DESCRIPTION:Titel: „Recent results on spectral properties of quantum gra phs and Archimedean tilings”\nAbstract: In the first part of the talk we study the spectrum of finite compact quantum graphs and compare the eigen values of two different self-adjoint realizations of a given Schrödinger operator. We derive an explicit expression for the limiting value of the a verage of the differences of the eigenvalues and discuss its geometrical i nterpretation. In this context we shall also establish a so-called local W eyl law for general (local) self-adjoint boundary conditions. In the secon d part of the talk we shall have a look at the discrete normalized Laplaci an on Archimedean tilings with the aim of identifying those tilings for wh ich there exist infinitely degenerate eigenvalues (so-called flat bands). Our main purpose will then be to investigate robustness of existing flat b ands with respect to perturbations of the Laplacian. Our investigations wi ll lead to the identification of one particular Archimedean tiling - the S uper–Kagome tiling – whose spectral properties are outstandingly rich. This talk is based on joint work with P. Bifulco (Hagen)\, M. Täufer (Ha gen)\, and J. Wintermayr (Wuppertal).\nDer Vortrag findet statt am Mittwoc h\, den 12.07.2023 um 17:15 Uhr im Raum W01 0-006\nInteressierte sind herz lich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Titel: „Recent results on spectral properties of quantum graphs and Archimedean tilings”
\n
Abstract: In the first part of the ta lk we study the spectrum of finite compact quantum graphs and compare the eigenvalues of two different self-adjoint realizations of a given Schrödi nger operator. We derive an explicit expression for the limiting value of the average of the differences of the eigenvalues and discuss its geometri cal interpretation. In this context we shall also establish a so-called lo cal Weyl law for general (local) self-adjoint boundary conditions. In the second part of the talk we shall have a look at the discrete normalized La placian on Archimedean tilings with the aim of identifying those tilings f or which there exist infinitely degenerate eigenvalues (so-called flat ban ds). Our main purpose will then be to investigate robustness of existing f lat bands with respect to perturbations of the Laplacian. Our investigatio ns will lead to the identification of one particular Archimedean tiling - the Super–Kagome tiling – whose spectral properties are outstandingly rich. This talk is based on joint work with P. Bifulco (Hagen)\, M. Täufe r (Hagen)\, and J. Wintermayr (Wuppertal).
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Der Vortrag findet stat t am Mittwoch\, den 12.07.2023 um 17:15 Uhr im Raum W01 0-006
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Interessierte sind herzlich eingeladen.
LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-im-rahmen-des-zesob-kolloquiums-1 DTSTAMP:20240219T132737Z DTSTART:20230626T163000Z SUMMARY:Vortrag im Rahmen des ZeSOB-Kolloquiums DESCRIPTION:Im Rahmen des ZeSOB-Kolloquiums spricht\nFrau Dr. Anne Vesely (Universität Bremen)\nzum Thema: „Post-selection inference in multivers e analysis“\nMontag\, 26.06.23\, 16:30 Uhr (s.t.) in W1 0-006\noder onli ne in BBB https://meeting.uol.de/b/pet-ihv-p2z-min\nAlle Interessierten au s dem IfM sind herzlich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Im Rahmen des ZeSOB-Kolloquiums spricht
\n
Frau Dr. Anne Vesely (Universität Bremen)
\n
zum Thema: „Pos t-selection inference in multiverse analysis“
\n
Montag\, 26.06.23\ , 16:30 Uhr (s.t.) in W1 0-006
\n
oder online in BBB https://meeting.uol.de/b/pet-ihv-p2z-mi n
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Alle Interessierten aus dem IfM sind herzlich eingeladen.
LOCATION:W01 0-006 (https://meeting.uol.de/b/pet-ihv-p2z-min) END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-dr-kathrin-akinwunmi-1 DTSTAMP:20240219T135059Z DTSTART:20230524T171500Z SUMMARY:Lecture: Dr Kathrin Akinwunmi DESCRIPTION:Title: "Algebraic thinking in arithmetic lessons at primary le vel"\nAbstract : Algebraic thinking is a fundamental component of maths te aching\, even if it is not explicitly mentioned in the national primary sc hool standards. It is inextricably interwoven with the content area of pat terns and structures\, which is known to be an essential core of maths tea ching and permeates all other content areas. Algebraic thinking means expl oring patterns and understanding their underlying structures.\nThe lecture will begin with a characterisation of algebraic thinking and an associate d differentiation of the terms patterns and structures. Subsequently\, two studies will be presented in which generalisation processes of primary sc hool children are considered from an epistemological perspective.\nThe lec ture will take place on Wednesday\, 24 May 2023 at 17:15 in room W01 0-006 \nInterested parties are cordially invited. X-ALT-DESC;FMTTYPE=text/html:
Title: "Algebraic thinkin g in arithmetic lessons at primary level"
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Abstract : Algebraic thinking is a fundamental component of maths teaching\, even if it is not explicitly mentioned in the national primary school standard s. It is inextricably interwoven with the content area of patterns and str uctures\, which is known to be an essential core of maths teaching and per meates all other content areas. Algebraic thinking means exploring pattern s and understanding their underlying structures.
\n
The lecture will begin with a characterisation of algebraic thinking and an associated diff erentiation of the terms patterns and structures. Subsequently\, two studi es will be presented in which generalisation processes of primary school c hildren are considered from an epistemological perspective.
\n
The le cture will take place on Wednesday\, 24 May 2023 at 17:15 in room W01 0-006
\n
Interested parties are cordially invited.
LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-svetlana-gurevich-1 DTSTAMP:20240219T135114Z DTSTART:20230517T171500Z DTEND:20230517T184500Z SUMMARY:Vortrag: Svetlana Gurevich DESCRIPTION:Titel: „Towards conservative solitons and reversibility in t ime delayed systems”\nAbstract: Delayed interactions are a ubiquitous fe ature of many real-world systems and the time lags become important in sit uations where distant\, point-wise\, nonlinear nodes exchange information propagating at a finite speed or possess finite reaction times. Nonlinear time-delay systems (TDSs) not only pose a fundamental challenge for theore tical studies but are of crucial importance for applications ranging from traffic flow dynamics and economy to active matter systems and laser physi cs\, to name just a few. Furthermore\, external time-delayed feedback cont rol loops have proven to be an efficient tool for an effective non-invasiv e stabilization of unstable dynamical states. However\, in physics\, TDSs mostly have been limited to the study of dissipative dynamics. Recently an example of a photonic system modeled by a nonlinear\, time-reversible\, c onservative time-delayed system has been shown. In this talk we start with a basic review of TDSs and then review our recent theoretical results reg arding the existence of reversible conservative TDSs considering a dispers ive microcavity containing a Kerr medium coupled to a distant external mir ror. In the long delay limit\, the normal form identifies with the nonline ar Schrödinger equation\, thereby allowing for bright and dark solitons a lthough the lack of integrability can be observed at high energies. We unv eil some of the symmetries and conserved quantities and recover the Lugiat o-Lefever equation in the weakly dissipative regime.\nDer Vortrag findet s tatt am Mittwoch\, den 17.05.2023 um 17:15 Uhr im Raum W01 0-006\nInteress ierte sind herzlich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Titel: „Towards conserv ative solitons and reversibility in time delayed systems”
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Abstract: Delayed interactions are a ubiquitous feature of many real-world systems and the time lags become important in situations where distant\, point-wise\, nonlinear nodes exchange information propagating a t a finite speed or possess finite reaction times. Nonlinear time-delay sy stems (TDSs) not only pose a fundamental challenge for theoretical studies but are of crucial importance for applications ranging from traffic flow dynamics and economy to active matter systems and laser physics\, to name just a few. Furthermore\, external time-delayed feedback control loops hav e proven to be an efficient tool for an effective non-invasive stabilizati on of unstable dynamical states. However\, in physics\, TDSs mostly have b een limited to the study of dissipative dynamics. Recently an example of a photonic system modeled by a nonlinear\, time-reversible\, conservative t ime-delayed system has been shown. In this talk we start with a basic revi ew of TDSs and then review our recent theoretical results regarding the ex istence of reversible conservative TDSs considering a dispersive microcavi ty containing a Kerr medium coupled to a distant external mirror. In the l ong delay limit\, the normal form identifies with the nonlinear Schröding er equation\, thereby allowing for bright and dark solitons although the l ack of integrability can be observed at high energies. We unveil some of t he symmetries and conserved quantities and recover the Lugiato-Lefever equ ation in the weakly dissipative regime.
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Der Vortrag findet statt a m Mittwoch\, den 17.05.2023 um 17:15 Uhr im Raum W01 0-006
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Interessierte sind herzlich eingeladen.
LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-lecture-kai-siedenburg-1 DTSTAMP:20240129T092753Z DTSTART:20230125T171500Z SUMMARY:Lecture: Kai Siedenburg DESCRIPTION:Since at least Pythagoras\, mathematics has shaped reasoning a bout the scientific basis of music. In this talk\, I will first discuss se lected examples of the music-math connection\, focusing on theories of mus ical scales\, consonance\, and timbre (tone quality). Among a review of ex amples on the formation of musical scales\, I will explain how recent rese arch on music perception has demonstrated nconsistencies of classic mathem atical theories of musical scales and consonance. I will make a case for f ully implemented models of auditory perception as critical tools for under standing music perception. Finally\, I will provide illustrations from my own work on the auditory modeling of the perception of timbre and pitch.\n The lecture will take place on Wednesday\, 25.01.2023 at 17.15 in room W01 0-006.\nInterested persons are welcome to attend. X-ALT-DESC;FMTTYPE=text/html:
Since at least Pythagoras\, mathematics ha s shaped reasoning about the scientific basis of music. In this talk\, I w ill first discuss selected examples of the music-math connection\, focusin g on theories of musical scales\, consonance\, and timbre (tone quality). Among a review of examples on the formation of musical scales\, I will exp lain how recent research on music perception has demonstrated nconsistenci es of classic mathematical theories of musical scales and consonance. I wi ll make a case for fully implemented models of auditory perception as crit ical tools for understanding music perception. Finally\, I will provide il lustrations from my own work on the auditory modeling of the perception of timbre and pitch.
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The lecture will take place on
We dnesday\, 25.01.2023 at 17.15 in room W01 0-006.
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Interest ed persons are welcome to attend.
LOCATION:W1 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-kolloquiumsvortrag-von-herrn-michael-j-jacobson-jr-1 DTSTAMP:20240219T135044Z DTSTART:20221130T170000Z DTEND:20221130T180000Z SUMMARY:Lecture: Michael J. Jacobson Jr. DESCRIPTION:Titel: "Unconditional Class Group Computation and Applications "\nAbstract: Class groups of number fields have been studied since the tim e of Gauss\, and in modern times have been used in applications such as in teger factorization and public-key cryptography. Computing class groups an d a system of fundamental units is a challenging problem for classical com puters\, for which no polynomial time algorithm is currently known. In add ition\, the fastest-known algorithm for computing these invariants has the shortcoming that the output is only correct under the assumption of the g eneralized Riemann hypothesis. This is fine for some cryptographic applica tions\, but in computational number theory applications such as tabulating class groups for testing unproved conjectures and solving Diophantine equ ations\, unconditional results are typically required. In this talk\, I wi ll discuss some of the applications where unconditional results are requir ed\, as well as recent results and on-going work on computing class groups and fundamental units unconditionally.\nDer Vortrag findet statt am Mittw och\, den 30.11.2022 um 17.15 - 18.45 Uhr im Raum W01 0-006 Interessierte sind herzlich eingeladen. X-ALT-DESC;FMTTYPE=text/html:
Titel: "Unconditional Cla ss Group Computation and Applications"
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Abstract: Class groups of number fields have been studied since the time of Gauss\, and in modern times have been used in applications such as integer factori zation and public-key cryptography. Computing class groups and a system of fundamental units is a challenging problem for classical computers\, for which no polynomial time algorithm is currently known. In addition\, the f astest-known algorithm for computing these invariants has the shortcoming that the output is only correct under the assumption of the generalized Ri emann hypothesis. This is fine for some cryptographic applications\, but i n computational number theory applications such as tabulating class groups for testing unproved conjectures and solving Diophantine equations\, unco nditional results are typically required. In this talk\, I will discuss so me of the applications where unconditional results are required\, as well as recent results and on-going work on computing class groups and fundamen tal units unconditionally.
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Der Vortrag findet statt am Mit twoch\, den 30.11.2022 um 17.15 - 18.45 Uhr im Raum W01 0-006 Int eressierte sind herzlich eingeladen.
LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-antrittsvorlesung-k-pankrashkin-g-junike-1 DTSTAMP:20240219T134748Z DTSTART:20220706T171500Z DTEND:20220706T184500Z SUMMARY:Antrittsvorlesung K. Pankrashkin+G. Junike DESCRIPTION: X-ALT-DESC;FMTTYPE=text/html: LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-antrittsvorlesung-m-wrobel-a-fruehbis-krueger-1 DTSTAMP:20240219T135023Z DTSTART:20220622T171500Z DTEND:20220622T184500Z SUMMARY:Inaugural lecture: M. Wrobel+A. Frühbis-Krüger DESCRIPTION: X-ALT-DESC;FMTTYPE=text/html: LOCATION: END:VEVENT BEGIN:VEVENT UID:calendarize-vortrag-renate-scheidler-1 DTSTAMP:20240219T135004Z DTSTART:20220518T171500Z DTEND:20220518T184500Z SUMMARY:Lecture: Renate Scheidler DESCRIPTION:Title: "The Ankeny-Artin-Chowla conjecture in real and false r eal-quadratic orders "\nAbstract : Algebraic number fields and their order s (subrings) are a research focus in number theory. The simplest examples are the quadratic number orders which\, despite their relatively simple st ructure\, are in many respects mysterious and the subject of a number of u nproven conjectures. The structural and algebraic properties of quadratic orders are fundamentally different depending on whether they are subrings of the real or merely of the complex numbers. In an unpublished note from 2014\, the French number theorist Henri Cohen made the surprising observat ion that the adjunction of a prime ideal to an imaginary-square order form s a number ring that has exactly the characteristics of a real-square orde r. Cohen described these rings as "fake real quadratic orders"\, i.e. as f alse (as opposed to real) real quadratic orders. This raises the natural q uestion of which of the assumptions mentioned above also apply to fake rea l quadratic orders. The fundamental units of real-quadratic orders of prim e discriminants are the subject of such a relatively controversial conject ure\, which goes back to Ankeny-Artin-Chowla. In this talk\, which assumes only basic algebra knowledge\, we will present a version of this conjectu re in false real-quadratic orders and report on the results of our very ex tensive numerical computations. This work was carried out jointly with my colleague Mike Jacobson and our former Masters student Hongyan Wang at the University of Calgary in Canada. The lecture will take place on Wednesday \, 18 May 2022 at 17:15 in room W01 0-006 Interested parties are cordially invited. X-ALT-DESC;FMTTYPE=text/html:
Title: "The Ankeny-Artin-Chowla co njecture in real and false real-quadratic orders "
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Abstract : Algebraic number fields and their orders (subrings) are a research focus in number theory. The simplest examples are the quadr atic number orders which\, despite their relatively simple structure\, are in many respects mysterious and the subject of a number of unproven conje ctures. The structural and algebraic properties of quadratic orders are fu ndamentally different depending on whether they are subrings of the real o r merely of the complex numbers. In an unpublished note from 2014\, the Fr ench number theorist Henri Cohen made the surprising observation that the adjunction of a prime ideal to an imaginary-square order forms a number ri ng that has exactly the characteristics of a real-square order. Cohen desc ribed these rings as "fake real quadratic orders"\, i.e. as false (as oppo sed to real) real quadratic orders. This raises the natural question of wh ich of the assumptions mentioned above also apply to fake real quadratic o rders. The fundamental units of real-quadratic orders of prime discriminan ts are the subject of such a relatively controversial conjecture\, which g oes back to Ankeny-Artin-Chowla. In this talk\, which assumes only basic a lgebra knowledge\, we will present a version of this conjecture in false r eal-quadratic orders and report on the results of our very extensive numer ical computations. This work was carried out jointly with my colleague Mik e Jacobson and our former Masters student Hongyan Wang at the University o f Calgary in Canada. The lecture will take place on Wednesday\, 18 May 2022 at 17:15 in room W01 0-006 Interested parties are cordi ally invited.
LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-institutspreisverleihung-der-jahrgangsbesten-1 DTSTAMP:20240219T134800Z DTSTART:20220504T171500Z DTEND:20220504T184500Z SUMMARY:Institutspreisverleihung der Jahrgangsbesten DESCRIPTION: X-ALT-DESC;FMTTYPE=text/html: LOCATION:W01 0-006 END:VEVENT BEGIN:VEVENT UID:calendarize-habilitationsvortrag-von-herrn-schober-1 DTSTAMP:20240219T134948Z DTSTART:20220420T171500Z DTEND:20220420T184500Z SUMMARY:Habilitation lecture by Mr Schober DESCRIPTION: X-ALT-DESC;FMTTYPE=text/html: LOCATION:W01 0-006 END:VEVENT END:VCALENDAR